I use a Samsung Evo UHS-l, 32GB Class 10, 48Mb/s. Apps and games run as well as they do when installed on my phone. It seems a bit smoother than the SanDisk Ultra 16GB Class 10 that was 32Mb/s which I had some trouble with.
Any class 10 probably OK as you won't need massive speeds. Still no harm in getting a future proofed one, especially if at some point you get a future pureview lumia.
I've got a Shield tablet and a SANDisk extreme didn't cut the mustard for gaming. Couldn't justify an Extreme Pro as a 64GB one in the UK is about ?99. Found a Lexar 633x for half the price and it is fast enough for games and the write speed is great for copying video to. I've just ordered another for my 1520 in anticipation of Denim.